Make software compositing work on Mac.

content/browser/renderer_host/render_widget_host_view_mac.mm

Index: content/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index 04051758b6540a2c48e5c62ad6282fb8ce251968..d8ee48152ed56a186637bcfd8ec921b32322cbec 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -420,6 +420,8 @@ RenderWidgetHostViewMac::RenderWidgetHostViewMac(RenderWidgetHost* widget)
       last_frame_was_accelerated_(false),
       text_input_type_(ui::TEXT_INPUT_TYPE_NONE),
       can_compose_inline_(true),
+      software_framebuffer_(new SoftwareFramebuffer(
+          this, RenderWidgetHostImpl::From(widget))),
       allow_overlapping_views_(false),
       use_core_animation_(false),
       is_loading_(false),
@@ -734,6 +736,7 @@ void RenderWidgetHostViewMac::WasShown() {
     web_contents_switch_paint_time_ = base::TimeTicks::Now();
   is_hidden_ = false;
   render_widget_host_->WasShown();
+  software_framebuffer_->WasShown();
 
   // We're messing with the window, so do this to ensure no flashes.
   if (!use_core_animation_)
@@ -758,6 +761,7 @@ void RenderWidgetHostViewMac::WasHidden() {
   // If we have a renderer, then inform it that we are being hidden so it can
   // reduce its resource utilization.
   render_widget_host_->WasHidden();
+  software_framebuffer_->WasHidden();
 
   // There can be a transparent flash as this view is removed and the next is
   // added, because of OSX windowing races between displaying the contents of
@@ -1221,6 +1225,24 @@ void RenderWidgetHostViewMac::EndFrameSubscription() {
   frame_subscriber_.reset();
 }
 
+void RenderWidgetHostViewMac::OnSwapCompositorFrame(
+    uint32 output_surface_id, scoped_ptr<cc::CompositorFrame> frame) {
+  // Only software compositor frames are accepted.
+  if (!frame->software_frame_data) {
+    render_widget_host_->GetProcess()->ReceivedBadMessage();
+    return;
+  }
+
+  GotSoftwareFrame();
+
+  software_framebuffer_->SwapToNewFrame(
+      output_surface_id,
+      frame->software_frame_data.get(),
+      frame->metadata.device_scale_factor);
+
+  [cocoa_view_ setNeedsDisplay:YES];
+}
+
 // Sets whether or not to accept first responder status.
 void RenderWidgetHostViewMac::SetTakesFocusOnlyOnMouseDown(bool flag) {
   [cocoa_view_ setTakesFocusOnlyOnMouseDown:flag];
@@ -1657,11 +1679,18 @@ void RenderWidgetHostViewMac::AcceleratedSurfaceRelease() {
 
 bool RenderWidgetHostViewMac::HasAcceleratedSurface(
       const gfx::Size& desired_size) {
-  return last_frame_was_accelerated_ &&
-         compositing_iosurface_ &&
-         compositing_iosurface_->HasIOSurface() &&
-         (desired_size.IsEmpty() ||
-          compositing_iosurface_->dip_io_surface_size() == desired_size);
+  if (last_frame_was_accelerated_) {
+    return (compositing_iosurface_ &&
+           compositing_iosurface_->HasIOSurface() &&
+           (desired_size.IsEmpty() ||
+               compositing_iosurface_->dip_io_surface_size() == desired_size));
+  } else {
+    return (software_framebuffer_->HasCurrentFrame() &&
+           (desired_size.IsEmpty() ||
+               software_framebuffer_->GetCurrentFrameSizeInDIP() ==
+                   desired_size));
+  }
+  return false;
 }
 
 void RenderWidgetHostViewMac::AboutToWaitForBackingStoreMsg() {
@@ -1771,6 +1800,9 @@ void RenderWidgetHostViewMac::GotAcceleratedFrame() {
 
     // Delete software backingstore.
     BackingStoreManager::RemoveBackingStore(render_widget_host_);
+
+    // Delete the software compositing frame if one exists.
+    software_framebuffer_->DiscardCurrentFrame();
   }
 }
 
@@ -2724,29 +2756,63 @@ void RenderWidgetHostViewMac::FrameSwapped() {
 - (void)drawBackingStore:(BackingStoreMac*)backingStore
                dirtyRect:(CGRect)dirtyRect
                inContext:(CGContextRef)context {
-  if (backingStore) {
+  content::SoftwareFramebuffer* software_framebuffer =
+      renderWidgetHostView_->software_framebuffer_->HasCurrentFrame() ?
+          renderWidgetHostView_->software_framebuffer_.get() : NULL;
+  DCHECK(!backingStore || !software_framebuffer);
+
+  if (backingStore || software_framebuffer) {
     // Note: All coordinates are in view units, not pixels.
-    gfx::Rect bitmapRect(0, 0,
-                         backingStore->size().width(),
-                         backingStore->size().height());
+    gfx::Rect bitmapRect(software_framebuffer ?
+        software_framebuffer->GetCurrentFrameSizeInDIP() :
+        backingStore->size());
 
     // Specify the proper y offset to ensure that the view is rooted to the
     // upper left corner.  This can be negative, if the window was resized
     // smaller and the renderer hasn't yet repainted.
-    int yOffset = NSHeight([self bounds]) - backingStore->size().height();
+    int yOffset = NSHeight([self bounds]) - bitmapRect.height();
 
     NSRect nsDirtyRect = NSRectFromCGRect(dirtyRect);
     const gfx::Rect damagedRect([self flipNSRectToRect:nsDirtyRect]);
 
     gfx::Rect paintRect = gfx::IntersectRects(bitmapRect, damagedRect);
     if (!paintRect.IsEmpty()) {
-      // if we have a CGLayer, draw that into the window
-      if (backingStore->cg_layer()) {
+      if (software_framebuffer) {
+        // If a software compositor framebuffer is present, draw using that.
+        gfx::Size sizeInPixels =
+            software_framebuffer->GetCurrentFrameSizeInPixels();
+
+        base::ScopedCFTypeRef<CGDataProviderRef> dataProvider(
+            CGDataProviderCreateWithData(
+                NULL,
+                software_framebuffer->GetCurrentFramePixels(),
+                4 * sizeInPixels.width() * sizeInPixels.height(),
+                NULL));
+
+        base::ScopedCFTypeRef<CGImageRef> image(
+            CGImageCreate(
+                sizeInPixels.width(),
+                sizeInPixels.height(),
+                8,
+                32,
+                4 * sizeInPixels.width(),
+                base::mac::GetSystemColorSpace(),
+                kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host,
+                dataProvider,
+                NULL,
+                false,
+                kCGRenderingIntentDefault));
+
+        CGRect imageRect = bitmapRect.ToCGRect();
+        imageRect.origin.y = yOffset;
+        CGContextDrawImage(context, imageRect, image);
+      } else if (backingStore->cg_layer()) {
+        // If we have a CGLayer, draw that into the window
         // TODO: add clipping to dirtyRect if it improves drawing performance.
         CGContextDrawLayerAtPoint(context, CGPointMake(0.0, yOffset),
                                   backingStore->cg_layer());
       } else {
-        // if we haven't created a layer yet, draw the cached bitmap into
+        // If we haven't created a layer yet, draw the cached bitmap into
         // the window.  The CGLayer will be created the next time the renderer
         // paints.
         base::ScopedCFTypeRef<CGImageRef> image(